Nice find!

I can't tell the model, but that looks like an integrated TSeng VGA chip. Can you get the model number off of it?

If that's a 4000AX, that's a nice chip to have for a 486. One of the best ISA VGA chips you can get. I'm not sure how the other TSeng chips compare.

It is a Tseng E4000/W32I. From my research, I think it is supposed to be one of the better integrated video chips from the time. That was pleasant surprise.

It's very (very!) fast but can have compatibility issues with more problematic games. All in all, it's a great chip.

A couple of updates:
I got the sound card, RAM, and CF adapter installed. I am waiting on a SCSI cable so no CD-ROM yet.

I was able to get DOS 6.22 and Windows 3.1 installed without any problems. A pleasant surprise was that the BIOS detected the full 4 GB size of the CF card so I didn't have to use drive overlay software. I just divided it into 2 x 2 GB partitions. I've got a couple games installed. Doom runs well enough at ~19 FPS. I only get about 12 FPS on Heretic but it is playable if you reduce the screen size a couple notches.

You are dedicated! I would have just used a standard CD-ROM temporarily to copy windows/drivers to the 2nd partition and hook it upto the network for anything else.
Your external SCSI is much cooler though.
You can always upgrade the CPU, DX2/66 will run Heretic ok, Dark Forces is still slow, may be better on DX4, never tried.

I got the external SCSI CD-ROM working. The drive got pretty beaten up in the mail, but it works, so whatever.

I switched everything over to PS2 and am using a KVM so I can switch over to the 486 from my "regular" computer easily.

The splotch above the Compaq logo is ink. I'm sure I could scrub it off with a magic eraser or something, but it is fine for now.

I have been researching CPU upgrades. The motherboard has settings for 25 or 33 Mhz bus speed and SX vs DX CPU. I doubt it supports 3.5v CPUs or write-back cache. I am probably looking at either a DX2-66 or an Overdrive chip of some sort (Intel ODPR model , or one of the AMD 5x86 models, no separate overdrive socket). The DX-2 would definitely be a lot cheaper, but there is a certain cool factor to going for overkill.

I ended up getting a DX4ODPR100 chip and installing it. I also threw in another 16 MB of RAM (28 MB total now). I won't ever need it on a system like this, but it was cheap so why not?

I did some before and after benchmarks with Phil's DOS Benchmark Pack.

Benchmark Name: SX-33 / DX4-100
3DBench 1.0c: 25.6 / 51.0
PC Player: 5.7 / 14.7
Doom (high detail, no-HUD): 14.1 / 30.9
Quake: NA / 9.7
Norton SysInfo 8.0 CPU: 71.9 / 126
Landmark: 158.2 Mhz / 520 Mhz
Topbench: 149 / 253

In most of these apps I got a 1.7-2x performance increase. PC Player and Landmark were closer to 3x. I'm wondering if PC Player is taking advantage of the FPU. Landmark looks like it is just so completely synthetic and unrealistic that I see this speed simply from the clock increase.

I think that I am pretty much done with hardware upgrades to this computer. It can play all the Doom engine games very smoothly which is most of what I was after. At this point it would be bottle-necked mainly by having no L2 cache, and there is no way to add it on this board.

Hey, I remember these Compaqs!
Mine (same look) had a 486DX2-66 installed and featured on-board audio (Compaq Business Audio ?)
Many years ago, I ran both DOS 6.20 and Windows 98SE on it - it was the slowest Windows 98 rig I ever had (probably because of the HDD). ^^
I can't remember that Tseng chip, though. I thought it had a Cirrus.. Strange. Maybe mine had a different chipset.

Tenorman wrote:

I ended up getting a DX4ODPR100 chip and installing it.

Good choice! 😀

Tenorman wrote:

I also threw in another 16 MB of RAM (28 MB total now).
I won't ever need it on a system like this, but it was cheap so why not?

True. Total memory lower than 64MiB is usually safe, btw.
If you install more, performance *may* degrade at some point because of insufficient cache memory.

I've got a question about your setup -- specifically the monitor.

My family had this same exact model when I was young, and I've kept it all these years with the hope of someday having room to set it up for DOS gaming. My concern is that the CRT monitor that came with the PC is going bad. I knew this before we packed it away but at the time I didn't think it would be hard to replace it later.

I came across a Windows Vista era LCD monitor that was a hand-me down. It's got a VGA connector, and I had a crazy thought that maybe I could connect it to the old 633. My concern would be the refresh rate, for starters . . . so I was wondering how you've got it hooked up to your LCD? Is there a converter in the KVM you're using?

The VGA LCD monitor I've got has a full 14 pins on the connector and I think older VGA ports only had 13, but I'm not 100% sure on that.

rubyjade wrote:

The VGA LCD monitor I've got has a full 14 pins on the connector and I think older VGA ports only had 13, but I'm not 100% sure on that.

When I've found myself in that situation I take a spare VGA cable, needle nose pliers, and snap the offending extra pin off one end of the cable.

Ah, thanks, that would be an easy fix if that's the only incompatibility issue. I probably don't even need to dig out a spare, I'd never use the monitor with a newer computer so that pin is irrelevant really. Either I can use it with my 486 or it goes to Staples.

That missing monitor pin is indeed a pain. My KVM cables don't have that extra pin, but you can just make yourself an "adapter" by breaking off the extra pin if you need to as was mentioned.

As far as your monitor goes: If it is from the Windows Vista era it is probably at least 10 years old. It will probably work. You could just try it out, but if you are curious you could dig out the manual and see if it supports some of the common DOS resolutions such as 720x400 (320x200 graphics mode will most likely "look" like this to the monitor) and 640x480.

I personally use an old 5:4 Dell LCD and it works fine. My newer widescreen monitors work as well, but they stretch the image to 16:9 which looks terrible.

Thanks so much for your answer! I was thinking I'd probably just have to give a try, but the 633 is at the bottom of a large stack of boxes . . . so I didn't want to dig it out if it wasn't likely at all to work. It looks like it might be worth it, though!

The monitor is one of the early widescreen monitors with a native 1366x768 resolution - but the manual states that it has two modes it calls 'Dos-mode', 720x400 & 640x480. Sounds promising. Since the monitor also has a dedicated button to switch between 4:3 and widescreen I might be able to get it to display without stretching. My biggest concern was the refresh rate (this monitor was old enough that it couldn't even display on my old PC because it didn't support the refresh rate the PC was set to -- I had to hook it up to my TV via HDMI to switch it back to a compatible refresh rate), but sounds like it's worth the effort to try it out and see.